Internal mold release compositions

ABSTRACT

An internal mold release system is provided which comprises (a) a carboxylic acid and (b) a compound selected from the group consisting of a fatty polyester, a fatty acid ester and a fatty amide.

FIELD OF THE INVENTION

The present invention is related to internal mold release systems. Morespecifically, the present invention is directed to internal mold releasesystems which are particularly useful in structural reaction injectionmolding applications.

BACKGROUND OF THE INVENTION

The present invention relates to internal mold release systems which maybe used in the preparation of reaction injected polyurethanes andpolyurea foam articles. These internal mold release systems areparticularly useful in manufacturing shaped resin components by thestructural reaction injection molding (SRIM) process, wherein a liquidstream of polyisocyanate is impingement mixed with at least one otherstream containing active hydrogen-containing liquids and optionally,catalysts, fillers, mold release systems, etc., and transferred to aheated metal mold. A glass mat or a mat of other structural fibers isplaced into the mold prior to the impingement mixing of the componentsso that the final product is a reinforced composite. SRIM processes areused commercially to manufacture various articles where high strengthand low weight are of importance. For example, SRIM processes are usedto manufacture interior trim substrates for automobiles, such as doorpanels, package trays, speaker enclosures and seat pans.

Developments in the chemistry of the polymer systems used in SRIMprocesses have resulted in urethane and urethane-urea polymers which aresufficiently cured to be demolded within about 50-90 seconds afterinjection. SRIM equipment has also improved so that the mechanics ofopening and closing the mold also require only about 40-70 seconds.Urethane polymers, being excellent adhesives, bond tenaciously to metalmaking it necessary to utilize a release agent so that parts can bequickly and easily removed from the mold without damage or distortion.

External mold release agents are used by applying the release agentdirectly to the surfaces of the mold. The mold must be completelycovered with the release agent, generally by spraying a solution or anemulsion of a soap or wax onto the surface of the mold. This procedurerequires a minimum of 30-60 seconds and must be repeated at least afterevery one to five parts, thus increasing the part to part cycle time byas much as 50%. Additionally, this constant spraying often causesexcessive mold release agent to build up on areas surrounding the moldsurface or on the mold surface itself. In this instance, the mold mustbe periodically wiped off and/or cleaned by solvent or detergent washwhich is both time consuming and costly for the part manufacturer.

Thus, it is clear that mold release agents or systems which may becontained in the reaction systems themselves, i.e., internal moldrelease agents or systems, would be advantageous in eliminating suchdifficulties, increasing productivity and reducing part cost. Variousinternal mold release agents have been proposed in an attempt to solvethese problems. For example, U.S. Pat. Nos. 4,546,154 discloses the useof 0.5-1.5 percent by weight of polysiloxane mold release agents inreaction injection molding systems for this purpose. However, suchmaterials have been found to provide an insufficient number of releasesto make their use commercially acceptable.

Certain acids, such as fatty acids and their esters, are known to act asmold release agents. For example, U.S. Pat. No. 4,098,731 discloses theuse of salts of saturated or unsaturated aliphatic or cycloaliphaticcarboxylic acids containing at least eight carbon atoms and tertiaryamines which do not contain amide or ester groups as release agents forpolyurethane foam production. U.S. Pat. No. 4,024,090 discloses the useof internal mold release agents which are the esterification reactionproducts of polysiloxanes and monocarboxylic or polycarboxylic acids.U.S. Pat. Nos. 5,128,807, 4,058,492, 3,993,606 and 3,726,952 all alsodisclose the use of carboxylic acids or their derivatives as moldrelease agents. U.S. Pat. No. 4,130,698 discloses the use of esters of afatty acid, such as glycerol trioleate, olive oil and peanut oil, as aprocessing aid. However, such systems have proven to be disadvantageousas they provide a relatively minor improvement in release performance,particularly in SRIM systems.

Other materials have been used to provide a release effect in moldingoperations. For example, U.S. Pat. No. 3,875,069 discloses lubricantcompositions useful in shaping thermoplastic material comprising: (A)mixed esters of (a) aliphatic, cycloaliphatic and/or aromaticdicarboxylic acids, (b) aliphatic polyols and (c) aliphaticmonocarboxylic acids with (B) esters of (1) dicarboxylic acids and longchained aliphatic monofunctional alcohols (2) long chained aliphaticmonofunctional alcohols and long-chained monocarboxylic acids and (3)full or partial esters of aliphatic polyols and long-chained aliphaticmonocarboxylic acids. U.S. Pat. No. 5,389,696 discloses a process forproducing a molded foam part using an internal mold release agent whichcomprises (a) 1-10% of mixed esters comprising the reaction product ofi) aliphatic dicarboxylic acids, ii) aliphatic polyols, and iii)monocarboxylic acids. This patent specifically excludes the esters ofthe U.S. Pat. No. 3,875,069. However, as with other internal releaseagents, the release materials disclosed in these patents have notdemonstrated the ability to provide consistently good results.

SUMMARY OF THE INVENTION

Accordingly, it can be seen that there is a need for internal moldrelease systems which provide a sufficient number of releases to makethem suitable for widespread commercial use. Thus, it is an objective ofthe present invention to provide internal mold release systems whichresult in a significantly higher number of releases in comparison toknown systems. It is a further objective of the present invention toprovide internal mold release systems which are particularly suitablefor use in SRIM systems.

The above-mentioned objectives are attained by the present inventionwhich is directed to internal mold release systems which provide animprovement over known systems. The present internal mold releasesystems have been found to be particularly useful in SRIM applications.The present internal mold release systems comprise a combination ofmaterials which demonstrate a synergistic release activity and provideimproved release results in comparison to known systems.

The present invention is directed to internal mold release systemscomprising (a) a carboxylic acid and (b) a compound selected from thegroup consisting of a fatty polyester, a fatty acid ester and a fattyamide. The present invention is further directed to reaction systemscomprising an organic polyisocyanate, a compound containing a pluralityof isocyanate-reactive groups and the internal mold release systemdescribed above, as well as processes utilizing such systems.

DETAILED DESCRIPTION OF THE INVENTION

The present internal mold release systems comprise (a) a carboxylic acidand (b) a compound selected from the group consisting of a fattypolyester, a fatty acid ester and a fatty amide. The term "fatty" asused in the context of the invention means compounds comprising 8 ormore carbon atoms and preferably 12 or more carbon atoms. Preferably,these compounds are aliphatic hydrocarbons and most preferably, linearaliphatic hydrocarbons. It has been found by the present inventor that acombination of components (a) and (b) demonstrate synergistic effects.That is, although components (a) and (b) each have mold releaseproperties when used alone, their combination is surprisingly moreeffective than either component used alone.

Although not wishing to be bound by any single theory, it is the beliefof the present inventor that the internal mold release systems of thepresent invention provide release activity due to the reaction of thecarboxylic acid with the isocyanate to form an amide. It is believedthat this amide material prevents the normally tenacious sticking of theisocyanate to the mold. Such activity, in synergistic combination withthe lubricating effects of the additional fatty material, provide themold release activity attributable to the present compositions.

In general, any carboxylic acid compounds containing an aliphatichydrocarbon chain are useful in the present mold release systems.However, it is preferred that the carboxylic acid be liquid soluble orsoluble in polyol blends. In general, useful carboxylic acid compoundscomprise about 3 to about 100, preferably about 6 to about 54 and mostpreferably about 18 to about 36 carbon atoms. The carboxylic acidcompounds should also have an acid functionality of about 1 to about 4and preferably about 1 to about 2. It has been found that the releaseactivity of the present systems increases with decreasing functionalityof the carboxylic acid compound. Both mono-acids and dimer acids may beused in the present compositions in concentrations of 0 to 95% (of thecarboxylic acid component) while the trimer (and higher functionality)content of the acid compounds may range from about 1 to about 60%.

Useful carboxylic acid compounds include polymerized oleic acid, oleicacid, adipic acid, lauric acid, stearic acid, hydroxystearic acid,terephthalic acid, behenic acid, arachidonic acid, linoleic acid,linolenic acid, ricinoleic acid and mixtures thereof. Preferably, thecarboxylic acid compound used in the present system is oleic acid orpolymerized oleic acid available commercially as HYSTRENE® 3695, 3675 or5460 from Witco Chemicals. The carboxylic acid component shall generallybe used in an amount of about 0.5 to about 5.0%, preferably about 1.5 toabout 2.5% and most preferably about 2% by weight of the total reactionsystem.

The carboxylic acid compounds used in the present internal releasesystems are present as the amine salts thereof. Useful salts includethose of primary, secondary and/or tertiary amines, although it ispreferred to use salts of tertiary amines. It is understood that theterm "amine" as used herein is meant to include othernitrogen-containing organic bases capable of forming salts withcarboxylic acids. These include amidine and guanidine compounds. Usefulsalts include those of tertiary aliphatic amines or aromatic amineswhich contain other isocyanate-reactive functional groups, such ashydroxyl groups, primary or secondary amino groups, amide groups, estergroups, urethane groups or urea groups. Moreover, it is contemplatedthat useful salts may contain more than one tertiary amine group permolecule.

Preferred tertiary aliphatic amines for use in the present inventioninclude N,N-dimethylcyclohexylamine, triethylene diamine,bis-(dimethylamino)-diethyl ether, N-ethyl-morpholine,N,N,N',N',N"-pentamethyl diethylenetriamine, N,N-dimethylaminopropylamine and aliphatic tertiary amine-containing amides ofcarboxylic acids, such as the amides of N,N-dimethyl aminopropylaminewith stearic acid, oleic acid, hydroxystearic acid and dihydroxystearicacid.

Useful tertiary aliphatic amine salts include those prepared by thereaction of oleic or polymerized oleic acid with triethanolamine,triisopropanolamine N-methyl diethanolamine, N,N-dimethyl ethanolamineand mixtures thereof.

Commercially available tertiary aliphatic amines include the POLYCAT®series of amines and the DABCO® amine catalysts both available from AirProducts Inc.

The second component of the internal mold release systems of the presentinvention is a compound selected from (1) a fatty polyester, (2) a fattyacid ester, and (3) a fatty amide or mixtures thereof. In general, thiscomponent should be contained in the present internal mold releasecompositions in an amount of about 0.5 to 5.0, preferably about 1.5 toabout 3.5, and most preferably about 2% based upon the weight of theentire system.

Fatty polyesters suitable for use in the present system includepolyesters having a number average molecular weight of about 500 toabout 12,000, preferably about 800 to about 5000, more preferably about1000 to about 4000 and most preferably about 2000 to about 3000. Usefulfatty polyesters are generally mixed esters comprising the reactionproduct of three monomers: (1) a monofunctional monomer; (2) adifunctional monomer; and (3) a polyfunctional monomer (i.e.,trifunctional or higher). The `functionality` of these monomers arisesfrom hydroxyl groups, acid groups, or derivatives thereof. Each ofmonomers (1), (2) and (3) may independently comprise from about 2 toabout 54 and preferably about 2 to about 18 carbon atoms.

Preferably, the fatty polyesters used in the present systems are mixedesters comprising the reaction product of (i) aliphatic dicarboxylicacids, (ii) aliphatic polyols and (iii) fatty monocarboxylic acidswherein the monocarboxylic acid comprises about 12 to about 30 carbonatoms, preferably about 16 to about 20 carbon atoms. Useful fattypolyesters include those disclosed in U.S. Pat. No. 3,875,096 which isincorporated herein by reference.

More preferably, the fatty polyesters utilized in the present internalmold release systems comprise the reaction product of (i) adipic acid,(ii) pentaerythritol and (iii) oleic acid. Suitable compounds areavailable commercially as LOXIOL® G-71S available from HenkelCorporation.

The fatty acid ester compounds useful in the present invention containat least about 22 carbon atoms and preferably at least about 31 carbonatoms. The maximum number of carbon atoms in the fatty acid ester islimited only where the carbon number causes the material to beunsuitable for blending with or into a polyol. Fatty acid esterssuitable for use in the present invention include the esters of stearicacid, oleic acid, linoleic acid, linolenic acid, adipic acid, behenicacid, arachidic acid, montanic acids, isostearic acid, polymerized acidsand mixtures thereof.

Examples of suitable fatty acid esters include butyl stearate, tridecylstearate, glycerol trioleate, isocetyl stearate, ditridecyl adipate,stearyl stearate, glycerol tri-(12-hydroxy) stearate, dioctyl dimerateand ethylene glycol distearate. Preferably, the fatty acid ester istridecyl stearate. Commercially available fatty acid esters suitable foruse in the present invention include the KEMESTER® series of acidsavailable from Witco Chemical, including KEMESTER® 5721, KEMESTER® 5822,KEMESTER® 3681, KEMESTER® 5654 and KEMESTER® 1000.

Useful fatty amide compounds include (1) primary amides comprising atleast 18 carbon atoms or (2) secondary or tertiary amides comprising atleast 34 carbon atoms. Suitable compounds are oleamide, stearamide,stearyl stearamide, 2-hydroxyethyl (12-hydroxy) stearamide and erucylerucamide. Commercially available fatty amides include the KEMAMIDE®series of fatty amide compounds also available from Witco Chemical.

The internal mold release systems of the present invention may beprepared by any suitable method known to those skilled in the art aswill be evident from the present specification. In general, the presentsystems may be prepared by simply mixing (a) the carboxylic acidcompound and the (b) fatty polyester, fatty acid ester or fatty amidecompound into the component of the reaction system containing aplurality of isocyanate-reactive groups or the "B side" of the reactionsystem. Although it may be formed separately, it is preferred that theacid salt compound be formed by mixing the free acid and the amine intothe bulk of the isocyanate-reactive component. The B side of the systemis then reacted with the polyisocyanate component or the "A side" of thesystem in order to form a final polyurethane product. The carboxylicacid compound and the fatty polyester, fatty acid ester or fatty amidecomponent are generally not reacted prior to their addition to the Bside of the reaction system as no reaction of these two components isdesired.

The present invention is further directed to reaction systems for use inSRIM processes comprising, in part, the present internal mold releasesystems. The reaction systems also comprise an organic polyisocyanateand a component containing at least one compound comprising a pluralityof isocyanate-reactive groups. The isocyanate-reactive component willgenerally contain the present mold release systems.

The organic polyisocyanates useful in the present invention are thosehaving a number average isocyanate functionality in the range of fromabout 1.8 to about 4.0. Preferably, the number average isocyanatefunctionality is from about 2.3 to about 3.0.

The organic polyisocyanates which may be used in the present systemsinclude any of the aliphatic, cycloaliphatic, araliphatic, or aromaticpolyisocyanates known to those skilled in the art, especially those thatare liquid at room temperature. Examples of suitable polyisocyanatesinclude 1,6-hexamethylene diisocyanate, isophorone diisocyanate,1,4-cyclohexane diisocyanate, 4,4'dicyclohexylmethane diisocyanate,1,4-xylylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluenediisocyanate, 2,6-toluene diisocyanate, 4,4'diphenylmethane diisocyanate(4,4'-MDI), 2,4'diphenylmethane diisocyanate (2,4'-MDI), polymethylenepolyphenylene polyisocyanates (crude or polymeric MDI) and 1,5naphthylene diisocyanate. Mixtures of these polyisocyanates can also beused. Moreover, polyisocyanate variants, i.e., polyisocyanates whichhave been modified by the introduction of urethane, allophanate, urea,biuret, carbodiimide, uretonimine, isocyanurate and/or oxazolidoneresidues can also be used in the present systems.

In general, aromatic polyisocyanates are preferred for use in thepresent reaction systems. The most preferred aromatic polyisocyanatesare 4,4'-MDI, 2,4'-MDI, polymeric MDI, MDI variants and mixturesthereof. Isocyanate-terminated prepolymers may also be employed. Suchprepolymers are generally prepared by reacting an excess of polymeric orpure isocyanate with polyols, including aminated polyols, imine- orenamine-modified polyols, polyether polyols, polyester polyols orpolyamines. Psuedoprepolymers, which are a mixture of prepolymer and oneor more monomeric di- or polyisocyanates, may also be used.

Commercially available polyisocyanates useful in the present reactionsystems include the RUBINATE® series of polymeric isocyanates availablefrom ICI Americas Inc.

In most cases, the component of the present reaction systems containingat least one compound containing a plurality of isocyanate-reactivegroups is a combination of at least two isocyanate-reactive compounds.Optionally, at least one of these is a softblock component. Softblockcomponents useful in the present reaction system include thoseconventionally used in the art. The term "softblock" is well known tothose in the art. It is the soft segment of a polyurethane, realizingthat the polyurethane may encompass isocyanurate rings, urea or otherlinkages. The isocyanate-reactive compound(s) also generally comprisesat least one chain extender and/or cross-linker.

Isocyanate-reactive materials which furnish softblock segments are wellknown to those skilled in the art. Such compounds generally have anumber average molecular weight of at least about 1500 and preferablyabout 1500 to about 8000, a number-average equivalent weight of fromabout 400 to about 4000 preferably from about 750 to about 2500, and anumber-average functionality of isocyanate-reactive groups of about 2 toabout 10 and preferably from about 2 to about 4. Such compounds includee.g., polyether or polyester polyols comprising primary or secondaryhydroxyl groups. Preferably, the softblock segments comprise about 0 toabout 30 wt % and more preferably about 0 to about 20 wt % of theisocyanate-reactive species of the compound containing a plurality ofisocyanate-reactive groups. It is most preferred that theisocyanate-reactive compound(s) comprise (a) about 0 to about 20 wt % ofat least one polyol having a molecular weight of 1500 or greater and afunctionality of 2 to 4; (b) about 70-98% wt % of at least one polyolhaving a molecular weight of between about 200 and 500 and afunctionality of about 2 to about 6; and (c) about 2 to about 15 wt % ofat least one polyol having a functionality of about 2 to about 4 and anumber average molecular weight of less than 200. All functionalitiesand molecular weights described herein with respect to polymericmaterials are "number average". All functionalities and molecularweights described with respect to pure compounds are "absolute".

Suitable polyether polyols which can be employed in the present reactionsystems include those which are prepared by reacting an alkylene oxide,halogen-substituted or aromatic-substituted alkylene oxide or mixturesthereof with an active hydrogen-containing initiator compound.

Suitable oxides include, for example, ethylene oxide, propylene oxide,1,2-butylene oxide, styrene oxide, epichlorohydrin, epibromohydrin, andmixtures thereof.

Suitable initiator compounds include water, ethylene glycol, propyleneglycol, butanediol, hexanediol, glycerine, trimethylol propane,pentaerythritol, hexanetriol, sorbitol, sucrose, hydroquinone,resorcinol, catechol, bisphenols, novolac resins, phosphoric acid andmixtures thereof.

Suitable initiators include, for example, ammonia, ethylenediamine,diaminopropanes, diaminobutanes, diaminopentanes, diaminohexanes,diethylenetriamine, triethylenetetramine, tetraethylenepentamine,pentamethylenehexamine, ethanolamine, aminoethylethanolamine, aniline,2,4-toluenediamine, 2,6-toluenediamine, 2,4'-diaminodiphenylmethane,4,4'-diaminodiphenylmethane, 1,3-phenylenediamine, 1,4-phenylenediamine,naphthylene-1,5-diamine, triphenylmethane 4,4',4'"-triamine,4,4'-di(methylamino)diphenylmethane, 1,3-diethyl-2,4-diaminobenzene,2,4-diaminomesitylene, 1-methyl-3,5-diethyl-2,4-diaminobenzene,1-methyl-3,5-diethyl-2,6-diaminobenzene,1,3,5-triethyl-2,6-diaminobenzene,3,5,3',5'-tetra-ethyl-4,4'-diamino-diphenylmethane and amine aldehydecondensation products such as the polyphenylpolymethylene polyaminesproduced from aniline and formaldehyde and mixtures thereof.

Suitable polyester polyols include, for example, those prepared byreacting a polycarboxylic acid or anhydride with a polyhydric alcohol.The polycarboxylic acids may be aliphatic, cycloaliphatic, aromaticand/or heterocyclic and may be substituted (e.g., with halogen atoms)and/or unsaturated. Examples of suitable carboxylic acids and anhydridesinclude succinic acid; adipic acid; suberic acid; azelaic acid; sebacicacid; phthalic acid; isophthalic acid; terephthalic acid; trimelliticacid; phthalic acid anhydride; tetrahydrophthalic acid anhydride;hexahydrophthalic acid anhydride; tetrachlorophthalic acid anhydride;endomethylene tetrahydrophtalic acid anhydride; glutaric acid anhydride;maleic acid; maleic acid anhydride; fumaric acid; dimeric and trimericfatty acids, such as those of oleic acid, which may be in admixture withmonomeric fatty acids. Simple esters of polycarboxylic acids may also beused, such as terephthalic acid dimethyl ester, therephthalic acidbisglycol ester and mixtures thereof.

Examples of suitable polyhydric alcohols include ethylene glycol,1,2-propylene glycol; 1,3-propylene glycol; 1,3-, 1,4-, 1,2- and2,3-butylene glycol; 1,6-hexane diol; 1,8-octane diol; neopentyl glycol;cyclohexane dimethanol (1,4-bis-hydroxylmethyl cyclohexane);2-methyl-1,3-propane diol, glycerol; trimethylol propane; 1,2,6-hexanetriol,; 1,2,4-butane triol; trimethylol ethylene; pentaerythritol;quitinol; mannitol; sorbitol; methylglycoside; diethylene glycol;triethylene glycol; tetraethylene glycol; polyethylene glycols;dipropylene glycol; polypropylene glycols; dibutylene glycol;polybutylene glycols and the like. The polyesters may contain someterminal carboxy groups although preferably they arehydroxyl-terminated. It is also possible to use polyesters of lactonessuch as caprolactone, or hydroxy carboxylic acids such as hydroxycaproic acid or hydroxyacetic acid.

The isocyanate-reactive component of the present reaction systems mayfurther comprise chain extenders and/or cross-linking agents. Suitablechain extenders or cross-linking agents will be evident to those skilledin the art from the present disclosure. In general, useful chainextenders are those having a formula weight below about 750 andpreferably about 62 to about 750 and a functionality of about 2.Suitable chain extenders may be selected from polyols such as ethyleneglycol, diethylene glycol, butanediol, dipropylene glycol andtripropylene glycol; aliphatic and aromatic amines, e.g., 4,4'-methylenedianilines having a lower alkyl substituent positioned ortho to each Natom; certain imino-functional compounds such as those disclosed inEuropean Patent Applications Nos. 284 253 and 359 456 and certainenamino-functional compounds such as those disclosed in European PatentApplication Nos. 359 456 having 2 isocyanate-reactive groups permolecule.

Suitable cross-linking agents include glycerol, oxyalkylated glycerol,pentaerythritol, sucrose, trimethylolpropane, sorbitol and oXyalkylatedpolyamines. The functionality of the cross-linking agents may range from3 to about 8, preferably 3 to about 4, and the molecular weight may varybetween the same ranges as disclosed above with regard to the chainextender. A preferred class of crosslinking agents includesoxypropylated derivatives of glycerol having a number average molecularweight of about 200 to about 750, glycerol and mixtures thereof.

A preferred isocyanate-reactive compound for use in the present reactionsystem is a propylene oxide adduct of glycerol having a functionality of3 and an hydroxyl equivalent weight of 86 available as RUBINOL® R-015from ICI Americas Inc. Blends of this polyol with glycerol are alsouseful in the present invention. In this instance, the weight ratio ofthe isocyanate-reactive compound to glycerol may be about 99:1 to about50:50, preferably about 98:2 to about 90:10 and most preferably about95:5 to about 90:10. This blend preferably comprises about 70 to about98 and preferably about 80 to about 95% by weight of theisocyanate-reactive compound(s) in the present reaction systems.

Preferably the isocyanate-reactive component of the present inventioncontains water or other blowing agent(s) in addition to theisocyanate-reactive compounds discussed above. Blowing agents suitablefor use with the present system are those conventionally used in theart, and include physical blowing agents such as water,chlorofluorocarbons and hydrocarbons; and chemical blowing agents, suchas hydroxyfunctional cyclic ureas, etc. The blowing agents should beused in amounts up to about 10%, preferably about 0.1 to about 5% andmore preferably about 0.25 to about 4% by weight of the total "B side"of the system.

The reaction systems of the present invention may be prepared by anyconventional method which will be evident to one skilled in the art fromthe present disclosure. For example, the polyisocyanate component (or Aside) of the reaction system may be mixed with the B side inconventional low or high pressure impingement mixing machines known inthe art.

The polyisocyanate component and the number of isocyanate-reactivecomponent(s) are mixed at suitable weight ratios such that the ratio ofthe number of isocyanate groups to isocyanate-reactive groups (commonlyknown as the index) is from about 75 to about 150%, with the provisothat when catalysts for the trimerization of isocyanates are used, theindex may extend up to about 500%. Preferably, the index is from about90 to about 115 and more preferably about 95 to about 105%.

The present reaction systems may further comprise conventionally usedadditives, such as flame retardants and catalysts, as needed forparticular applications. Useful flame retardants include phosphonates,phosphites and phosphates, such as tris-(2-chloroisopropyl) phosphate(TCPP), dimethyl methyl phosphonate, ammonium polyphosphate and variouscyclic phosphates and phosphonate esters known in the art;halogen-containing compounds known in the art, such as brominateddiphenyl ether and other brominated aromatic compounds; melamine;antimony oxides, such as antimony pentoxide and antimony troxide; zinccompounds such as zinc oxide; alumina trihydrate; and magnesiumcompounds, such as magnesium hydroxide. The flame retardants may be usedin any suitable amount which will be evident to those skilled in the artfrom the present disclaimers. However, it is preferred that the flameretardant be used in an amount of 0 to 55% of the B side of the system.

Useful catalysts include tertiary amines, organometallic compounds andamides of saturated or unsaturated C₁₂ -C₂₄ fatty acids and di, tri ortetra-aminoalkanes having at least one catalytic amino group and atleast one reactive amino group. Fatty amido-amines having hydroxylsubstituents may also be used. A particularly preferred amido-aminecompound is the reaction product N,N-dimethyl propyl diamine and a mixedfatty carboxylic acid available as BUSPERSE® 47 from BuckmanLaboratories. The catalysts are used in amounts necessary for aparticular application which will be evident to one skilled in the artfrom the present disclosure.

Other conventional additives generally used in the art may also be usedwith the reaction systems of the present invention. Examples of suitableadditives include fillers, such as calcium carbonate, silica, mica,wollastonite, wood flour, melamine, glass or mineral fibers, glassspheres, etc.; pigments; surfactants; and plasticizers. Such additiveswill be used in amounts which will be evident to one skilled in the artfrom the present disclosure.

The present invention is still further directed to a process forproducing molded articles comprising reacting (1) an organicpolyisocyanate; (2) a compound containing a plurality ofisocyanate-reactive groups; and (3) an internal mold release systemcomprising (a) a carboxylic acid and (b) a fatty polyester, a fattyester, a fatty amide or mixtures thereof.

In the reaction system of the present invention and the process forproducing molded articles utilizing the reaction system, the internalmold release system is used in an amount of from about 0.55 to about 18and preferably about 2.6 to about 6 parts by weight based upon theweight of the reaction system.

The present invention is especially suitable for use with SRIMtechniques which utilize a closed mold. However, the invention will findapplication in open mold processes which utilize spray techniques, i.e.,where the resin system is first sprayed over the mat and then the systemis allowed to cure either in an open or closed mold.

Parts prepared with SRIM processes are usually prepared with areinforcement mat pre-placed in the mold. The reaction system isinjected into the closed mold over the mat. The resulting part is amat-reinforced composite which is demolded after the reaction systemcures.

The reaction systems of the present invention may be used with anyreinforcement mat conventionally used in the SRIM art. Suitablereinforcement mats include woven or non-woven structural fibers such asglass, carbon, metal, graphite, silicon carbide, alumina, titania,boron, cellulosic, lignocellulosic, aromatic polyamide, polyester,polyolefin and mixtures thereof. The final reinforced molded article maycontain between 0.5 to about 95 wt % and preferably about 10 to about 70wt % of the reinforcing material. The diameter of the fibers is notcritical and may vary from about 0.001 to about 1.0 mm. The mat may beoptionally pretreated with sizing agents, coatings, adhesion promotersand other kinds of surface treatments known in the art.

In the process for producing molded articles according to the presentinvention, the surfaces of the molds must be pre-treated with knownexternal mold release agents or mixtures thereof. For example, the moldsurfaces may be treated with conventional external mold release agentssuch as soaps; and waxes, e.g., carnuba wax, montan wax, etc.; andmixtures thereof. It is preferred that the external release agents(s)used have a high melting point and demonstrate little or no transfer tothe molded parts.

The present invention will now be illustrated by reference to thefollowing specific non-limiting examples.

EXAMPLES

The following examples demonstrate the release properties provided bythe internal mold release systems of the present invention.

Example 1

Samples 1-6 and Comparative Formulations 1-3 were evaluated for releaseperformance. In each instance, the internal mold release system wasblended into the polyol component or the "B side" of the system. Thepolyol blends were prepared by simply blending all polyol componentslisted for each sample and formulation in Table 1 in a standard mixingvessel and then charging each composition into a Canon H-100 highpressure metering unit.

Components of the present formulations which are solid materials at roomtemperature were first melted and then added to a heated mixture of thepolyol component under high shear mixing to prepare the B side of thereaction system. The blend was maintained at a temperature high enoughso that the internal mold release system would not be percipitatedduring its addition. The blend was then allowed to cool during mixing.After cooling, water and catalyst were added to form the final "B side"mixture.

The release evaluations were conducted utilizing the polyol compositionsset forth in Table 1 as the B side of the reaction system and RUBINATE®8700 polyisocyanate available from ICI Americas Inc., as the "A side" ofthe system. RUBINATE® 8700 is a mixture of diisocyanato diphenylmethaneisomers with oligomeric polymethylene polyphenylene polyisocyanates andhas an NCO content of 31.5%.

Each reaction system was evaluated for release from a mold in a fullscale machine process. A standard Cannon H-100 high pressure meteringunit with an impingement mixing head was used. An aluminum door panelsubstrate mold mounted in a 75 ton Cannon press was used as the surfacefrom which release was determined. An open pour process was employedwherein the reaction system was injected into an open mold containing aglass mat. The glass mat used was a 1 oz./ft² of an N-754 continuousstrand non-woven glass mat available from Nico Fibers. The mold was thenclosed for the cure time of the foam as determined by the appropriategreen strength for the part, which was 90 seconds (see below). Aftercure, the mold was opened and the release of the LD-SRIM part wasobserved.

Prior to injection of the A and B side components, the mold was firststripped to bare metal by scrubbing with N-methyl-2-pyrrolidinone(commonly referred to as N-methyl pyrolidone) to remove any wax. TheN-methyl-2-pyrrolidinone was then removed by wiping the mold withmineral spirits. The mold was then waxed with a paste wax having a hightemperature use range. The wax used in Examples 1 and 2 was LH-1available from Chem Trend which has a use range of 185° F.-250° F.

The molding process was carried out under the following conditions:

    ______________________________________                                        Component Temperatures                                                                              85°                                                                           F.                                               Mold Temperature      155°                                                                          F.                                               Injection Pressure    2000   psi                                              Injection Rate        250    g/sec                                            Cure Time             90     sec                                              ______________________________________                                    

The release performance was evaluated by counting the number of releasesobtained on consecutive molded parts, i.e., without the furtherapplication of wax. The release evaluations were carried out until amaximum of forty parts were obtained, at which time the evaluation wasterminated.

                                      TABLE 1                                     __________________________________________________________________________    Polyol                                    Comp.                                                                              Comp.                                                                              Comp.                     Components  Form. 1                                                                            Form. 2                                                                            Form. 3                                                                            Form. 4                                                                            Form. 5                                                                            Form. 6                                                                            Form. 1                                                                            Form. 2                                                                            Form.                     __________________________________________________________________________                                                        3                         RUBINOL ® R015                                                                        100.0                                                                              100.0                                                                              100.0                                                                              100.0                                                                              100.0                                                                              100.0                                                                              100.0                                                                              100.0                                                                              100.0                     GLYCERINE   5.00 5.0  5.0  5.0  5.0  5.0  5.0  5.0  5.0                       L-5440      1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50                      Water       1.60 1.50 1.50 1.50 1.60 1.60 1.60 1.60 1.60                      POLYCAT ® 8                                                                           5.0  5.0  5.0  5.0  5.0  5.0  6.0  4.5  3.0                       HYSTRENE ® 3695                                                                       --   --   --   --   6.55 6.5  13.35                                                                              --   --                        Oleic acid  6.55 6.55 6.55 6.55 --   --   --   --   --                        KEMESTER ® 5721                                                                       5.75 --   --   --   5.75 --   --   12.13                                                                              --                        KEMESTER ® EGDS                                                                       --   6.55 --   --   --   --   --   --   --                        KEMAMIDE ® S180                                                                       --   --   6.55 --   --   --   --   --   --                        KEMAMIDE ® E221                                                                       --   --   --   6.55 --   6.50 --   --   13.30                     A/B mix ratio                                                                             1.62 1.60 1.60 1.60 1.62 1.63 1.62 1.65 1.64                      No. of releases                                                                           12   9    2    16   12   20   5    6    2                         __________________________________________________________________________

RUBINOL® R015 is oxypropylated glycerine having an OH number of 650available from ICI Americas Inc.

L-5440 is a silicone surfactant available from OSi Inc.

POLYCAT® 8 is an N,N-dimethyl-cyclohexyl amine catalyst available fromAir Products.

HYSTRENE® 3695 is polymerized oleic acid available from Witco Chemicals.

KEMESTER® 5721 is tridecyl stearate available from Witco Chemicals.

KEMESTER® EGDS is ethylene glycol distearate available from WitcoChemicals.

KEMAMIDE® S180 is stearyl stearamide available from Witco Chemicals.

KEMAMIDE® E221 is erucyl erucamide available from Witco Chemicals.

As can be seen from the data set forth in Table 1, the internal moldrelease systems containing a carboxylic acid and certain fatty acidesters or fatty amides according to the invention provide multiplerelease properties in SRIM systems.

Sample 3, which used stearyl stearamide as the fatty amide incombination with the carboxylic acid (polymerized oleic acid),demonstrated relatively inferior release properties due to inadvertentvariations in the mold temperature.

Example 1 demonstrates that improvements in release characteristics areobtained when the combination of materials presently claimed is used incomparison to one of the components alone. That is, Formulations 1 and 5which utilize the present invention showed significant improvement overComparative Formulations 1 and 2 which utilize only the carboxylic acidand fatty ester components alone, respectively. Likewise, Formulations 4and 6, which utilize the present invention demonstrate improved,synergistic effects versus Comparative Formulations 2 and 3 which usethe carboxylic acid and fatty amide components alone, respectively. Thissuperior, synergistic effect of the present components was unexpectedprior to this present invention.

Examples 2

The polyol compositions set forth in Tables 2, 3 and 4 were prepared inthe same manner as those set forth in Table 1 discussed above withreference to Example 1.

The release characteristics of the polyol compositions were alsoevaluated by preparing full scale parts in the manner described inExample 1. The "B side" of the reaction systems are those identified inTable 2. The "A side" of each system was RUBINATE® 8700 polyisocyanateas also used in Example 1.

                                      TABLE 2                                     __________________________________________________________________________    Polyol                              Comp Comp                                 Components Form 7                                                                             Form 8                                                                             Form 9                                                                             Form 10                                                                            Form 11                                                                            Form 4                                                                             Form 5                               __________________________________________________________________________    RUBINOL ® R015                                                                       100.0                                                                              100.0                                                                              100.0                                                                              100.0                                                                              100.1                                                                              100.0                                                                              100.0                                GLYCERINE  5.0  5.0  5.0  5.0  5.0  5.0  5.0                                  L-5440     1.50 1.50 1.50 --   --   1.50 1.50                                 L-1000     --   --   --   2.0  --   --   --                                   L-6980     --   --   --   --   1.50 --   --                                   Water      1.50 1.50 1.60 1.60 1.60 1.50 1.50                                 POLYCAT ® 8                                                                          5.00 5.00 5.00 5.00 4.00 5.0  5.0                                  DABCO ® 8800                                                                         --   --   0.50 --   --   --   --                                   DABCO ® 33 LV                                                                        --   --   --   0.65 0.65 --   --                                   FOAMREZ ® UL-32                                                                      --   --   --   0.15 0.15 --   --                                   PDI-4803   --   --   4.00 4.00 4.00 --   --                                   HYSTRENE ® 3695                                                                      6.50 6.50 6.50 6.50 6.50 --   --                                   IMR A      11.50                                                                              --   --   --   --   11.25                                                                              --                                   IMR B      --   11.50                                                                              6.75 5.00 3.30 --   11.25                                A/B Mix Ratio                                                                            1.55 1.55 1.56 1.59 1.61 1.62 1.62                                 No. of releases                                                                          40+  40+  40+  40+  27/32.sup.1                                                                        22   16                                   __________________________________________________________________________     .sup.1 Represents duplicate runs of the system.                          

                                      TABLE 3                                     __________________________________________________________________________    Polyol     Formulation                                                                          Formulation                                                                           Formulation                                                                          Formulation                                                                          Formulation                                                                           Formulation                                                                          Formulation            Components 12     13      14     15     16      17     18                     __________________________________________________________________________    RUBINOL ® R015                                                                       100.0  100.0   100.0  100.0  100.0   100.0  100.0                  GLYCERINE  5.0    5.0     5.0    5.0    5.0     5.0    5.0                    L-5440     --     --      1.50   1.50   1.50    1.50   --                     L-6980     1.50   1.50    --     --     --      --     1.50                   Water      1.60   1.60    1.65   1.60   1.60    1.60   1.60                   POLYCAT ® 8                                                                          4.00   4.00    4.50   4.00   4.00    4.00   4.00                   DABCO ® 33 LV                                                                        0.50   0.65    --     --     --      --     0.65                   FOAMREZ ® UL-32                                                                      --     0.15    --     --     --      --     0.15                   PDI-4803   --     4.00    --     --     --      --     4.0                    HYSTRENE ® 3695                                                                      6.50   6.50    4.90   3.25   --      --     --                     Oleic acid --     --      --     --     6.50    --     --                     TOFA acid  --     --      --     --     --      6.50   --                     Adipic acid                                                                              --     --      --     --     --      --     1.68                   IMR B      --     --      6.55   6.50   3.25    3.25   3.24                   IMR C      6.75   3.30    --     --     --      --     --                     Mix Ratio  1.60   1.61    1.63   1.65   1.66    1.66   1.67                   No. of releases                                                                          40+    18/19   40+    40+    34      27     14/11.sup.2            __________________________________________________________________________     .sup.2 Represents duplicate runs of this system.                         

                  TABLE 4                                                         ______________________________________                                                     Formula- Formula- Formula-                                                                             Formula-                                Polyol       tion     tion     tion   tion                                    Components   19       20       21     22                                      ______________________________________                                        RUBINOL ® R015                                                                         100.0    100.0    100.0  100.0                                   GLYCERINE    5.00     5.00     5.00   5.00                                    L-6980       1.50     1.50     1.50   1.50                                    Water        1.60     1.60     1.60   1.60                                    POLYCAT ® 8                                                                            2.50     4.00     4.00   4.00                                    DABCO ® 33 LV                                                                          0.65     0.65     0.65   0.65                                    FOAMREZ ® UL-                                                                          0.15     0.15     0.15   0.15                                    32                                                                            HYSTRENE ®                                                                             6.70     6.70     6.68   6.68                                    3695                                                                          IMR B        --       --       --     --                                      IMR C        3.35     3.35     3.35   3.35                                    BUSPERSE ® 47                                                                          6.70     --       --     --                                      KEMAMIDE ®                                                                             --       6.70     --     --                                      E221                                                                          Tallow diamine                                                                             --       --       4.00   --                                      TCPP         --       --       --     6.68                                    A/B Mix Ratio                                                                              1.62     1.59     1.63   1.57                                    No. of releases                                                                            40+      25       19     40+                                     ______________________________________                                    

L1000 and L6980 are poly(dimethylsiloxane) surfactants available fromOSi Chemicals.

DABCO® 33LV is 33% diethylene diamine octoate in dipropylene glycolavailable from Air Products.

DABCO® 8800 is acid blocked Dabco 33LV available from Air Products.

FOAMREZ® UL32 as a tin catalyst available from Witco Chemical.

PDI-4803 is a black pigment dispersed in a polyol available from Ferro.

IMR A, IMR B and IMR C are complex, mixed fatty polyesters fallingwithin the scope of the present invention.

BUSPERSE® 47 is a fatty amide of N,N-dimethyl propylene diamineavailable from Buckman Laboratories.

Formulations 7 to 18 demonstrate the excellent release propertiesimparted to LD-SRIM systems by an internal mold release systemcomprising a carboxylic acid and a fatty polyester. Of these,Formulations 9, 10 and 11, when directly compared to ComparativeFormulations 4 and 5 (which utilize the fatty polyesters alone),evidence the novel synergistic effects of the present invention.Formulations 19-22 further demonstrate the release results obtained withinternal mold release systems comprising a carboxylic acid, a fattypolyester and additional components, including fatty acid esters andfatty amides. Formulation 19 demonstrates the superior releaseproperties obtained with an internal mold release agent comprising acarboxylic acid, a fatty polyester and an amido-amine catalyst, such asBUSPERSE® 47. Formulations 20-21 demonstrate that excellent releaseproperties are obtained when a carboxylic acid is combined with a fattypolyester and a fatty amide. Formulation 22 demonstrates that noreduction in release activity occurs when the present internal moldrelease systems are combined with conventional flame retardants.

The present invention may be embodied in other specific forms withoutdeparting from the spirit and essential attributes thereof andaccordingly, reference should be made to the appended claims, ratherthan to the foregoing specification as indicating the scope of theinvention.

I claim:
 1. A reaction system comprising: (1) an organic polyisocyanate,(2) at least one compound containing a plurality of isocyanate-reactivegroups and (3) an internal mold release system comprising (a) acarboxylic acid and (b) a compound selected from the group consisting ofa fatty polyester, a fatty acid ester and a fatty amide.
 2. A reactionsystem as in claim 1 wherein said organic polyisocyanate is selectedfrom the group consisting of 4,4'-diphenylmethane diisocyanate,2,4'-diphenylmethanediisocyanate, polymethylenepolyphenylenepolyisocyanate, diphenylmethane diisocyanate variants and mixturesthereof.
 3. A reaction system as in claim 1, wherein said compoundcontaining a plurality of isocyanate-reactive groups is selected fromthe group consisting of polyester polyols and polyether polyols.
 4. Areaction system as in claim 1, wherein the carboxylic acid is selectedfrom the group consisting of polymerized oleic acid, oleic acid, adipicacid, lauric acid, stearic acid, hydroxystearic acid, terephthalic acid,behenic acid, arachidonic acid, linoleic acid, linolenic acid,ricinoleic acid and mixtures thereof.
 5. A reaction system as in claim4, wherein said fatty acid is polymerized oleic acid.
 6. A reactionsystem as in claim 1, wherein said fatty polyester has a number averagemolecular weight of 500-12,000.
 7. An internal mold release system as inclaim 5, wherein said fatty polyester is a mixed ester comprising thereaction product of (a) a monofunctional monomer; (b) a difunctionalmonomer; and (c) a polyfunctional monomer.
 8. A reaction system as inclaim 7, wherein said fatty polyester is a mixed ester comprising thereaction product of (i) aliphatic dicarboxylic acids, (ii) aliphaticpolyols and (iii) monocarboxylic acids comprising 12-30 carbon atoms. 9.A reaction system as in claim 8, wherein said fatty polyester comprisesthe reaction product (i) adipic acid, (ii) pentaerythritol and (iii)oleic acid.
 10. A reaction system as in claim 1, wherein said fatty acidester is selected from the group consisting of butyl stearate, tridecylstearate, glycerol trioleate, isocetyl stearate, ditridecyl adipate,stearyl stearate, glycerol tri-(12-hydroxy)stearate, dioctyl dimerate,ethylene glycol distearate.
 11. A reaction system as in claim 1, whereinsuch fatty amide is selected from the group consisting of oleamide,stearamide, stearyl stearamide, N-2-hydroxyethyl(12-hydroxy)stearamideand erucyl erucamide.
 12. A process for producing molded articlescomprising reacting (1) an organic polyisocyanate; (2) at least onecompound containing a plurality of isocyanate-reactive groups; and (3)an internal mold release system comprising (a) a carboxylic acid and (b)a compound selected from the group consisting of a fatty polyester, afatty acid ester and a fatty amide.
 13. A process as in claim 12 whereinsaid carboxylic acid is selected from the group consisting ofpolymerized oleic acid, oleic acid, adipic acid, lauric acid, stearicacid, hydroxystearic acid, terephthalic acid, behenic acid, arachidonicacid, linoleic acid, linolenic acid, rininoleic acid and mixturesthereof.
 14. A process as in claim 12 wherein said fatty polyester is amixed ester comprising the reaction product of (a) a monofunctionalmonomer; (b) a difuncitonal monomer; and (c) a polyfunctional monomer.15. A process as in claim 14 herein said fatty polyester is a mixedester comprising the reaction product of (i) aliphatic dicarboxylicacids; (ii) aliphatic polyols and (iii) monocarboxylic acids comprising12 to 30 carbon atoms.
 16. A process as in claim 15 wherein said fattypolyester comprises the reaction product of (i) adipic acid, (ii)pentaerythritol and (iii) oleic acid.
 17. A process as in claim 12,wherein said fatty acid ester is selected from the group consisting ofbutyl stearate, tridecyl stearate, glycerol trioleate, isocetylstearate, ditridecyl adipate, stearyl stearate, glyceroltri-(12-hydroxy)stearate, dioctyl dimerate, ethylene glycol distearate.18. A process as in claim 1 wherein said fatty amide is selected fromoleamide, stearamide, stearyl stearamide,N-2-hydroxyethyl(12-hydroxy)stearamide and erucyl erucamide.